Trophime delville



(No Model.)

DELVILLE'. VALVE GEAR.-

'NO. 574,400. Patented Jan.w5, 1897.

- UNITED STATES ATENT FFICE.

TROPHIME DELVILLE, OF BRUSSELS, BELGIUM.

VALVE-G EAR.

SPECIFICATION forming part of Letters Patent No. 574,400, dated January5, 1897.

Application filedOctoher 24:, 1893. Serial N0- 4=89.06Z. (No model-lPatented in Belgium April 26, I892. N0.99,442 in Germany July 22, 1892,No. 5,285; in France October 24, 1892. No. 225,149, and in EnglandMayZB, 1893, No. 10,388.

To all whom it may concern:

Be it known that 1, TROPHIME DELVILLE, engineer, a subject of the Kingof Belgium, residing at Brussels, Belgium, have invented new and usefulImprovements Connected with the ValveGear of Steam-Engines, (for whichpatents have been obtained in Belgium April 26, 1892, No. 99,442; inGermany July 22, 1892, No. D 5,285; in France October 24, 1892, No.225,149, and in Great Britain May 26, 1893, No. 10,388,) of which thefollowing is a full, clear, and exact description.

This invention has for its object to enable the admission of steam toand the discharge of the same from the cylinders of steam-engines havingdistributing slide-gear to take place as easilyas possible, in order toavoid the resulting over or back pressure, which is opposed to theadvantageous utilization of the steam, such back pressure being anunavoidable drawback in the lead imparted to a slidevalve by means of asuitable connection with the eccentric. I

This invention has for its object to provide an arrangement foroperating the free-running slidevalve in such a way that thereby, first,a very large opening of the inlet and outlet passages is brought about;secondly, a large linear lead of the inlet and outlet, and, thirdly,however, only a small angular lead for the inlet and outlet.

In order that my invention may be fully understood, I will proceed todescribe the same with reference to the accompanying drawings, inwhicl1- Figure l is a view graphically representing the course of thesliding block which is connected to the stem of the slide-valve. Figs. 2and 3 are views showing the simplest arrangem ent of the levers forproducing the desired results. Figs. at and 5 are modifications of thearrangement of the levers, and Fig. 6 is a diagrammatic View showing thevarious courses of the lead-lever.

In order to graphically represent the course of the slide-valvessuitable for producing the desired action, the Zeuners circular polardiagram must be drawn as an extended, flattened, or oval curve, as shownin Fig. l of the accompanying drawings, and it then appears from thecomparison of the figures that in the case of the dotted curve themaximum opening of the inlet-passages P P" is considerably greater thanthat produced by means of the circular course P P. that the linear leadto the inlet A A", is much greater than A A, but that the angular lead AI is considerably smaller than A I, from which the conclusion is drawnthat in the dotted oval course of the slidevalve the commencement of theinlet, which in the circular diagram with the same maximum openingstakes place too soon, is suitably delayed. In order, then, to carry outthis movement of the slide-valves theoretically ex= actly, that is tosay, to suitably accelerate or retard toward both sides the stroke ofthe valve, and that in a suitable proportion for producing an evenpiston speed, in other words, to describe the theoretically correct lineof curve corresponding to the desired object, the slide-valve operatedfrom the eccentric must be influenced in such a way that it only has thenormal speed at the moment when it is in a middle position, and fromthis moment, however, must be progressively accelerated toward bothsides in order to again resume the middle position with an equalprogressive retardation, so that at each stroke of the piston the slidemakes one half of its course with a progressive retardation and theother half of its course with a progressive acceleration. If thesealterations of speed are to take place by means of lever transmission inan eX- actly correct progression to the even strokes of the piston,there is only one possible mode of connecting the lead-lever with theremain ing parts of the engine in order to produce an absolutely correctmaintenance of the proportions, and this is characterized by one end ofthe lever makinga straight back-and-forward movement correspondingto thepiston-stroke, while the other end appears as a longer or shorterlever-arm opposite the point. of engagement of the slide-rod, accordingto the position of the slide, for which purpose the point of engagementof the eccentric rod which operates the lever must always lie betweenthe point of engagement of the sliderods and the straight end of thelever. These indispensable conditions for producing the desired resultare obtained in the simplest manner by the arrangement of lead-leversshown as a sketch in Figs. 2 and In these the lower end A of the leveris compulsorily moved backward and forward in a straight line, like thepiston, by being con- 5 nected with a cross-head, while the leveroscillates on the point of engagement B of the eccentric-rod and endsabove as a suitablyformed connecting-link C, which embraces theslide-block D, attached to the straight 1o slide-rod, so that then ateach to-and-fro movement of the lever-arm B, D is shortened orlengthened in alternate progression in proportion to the movement of thepiston, and thus the slide-valve undergoes in its course I 5 theabove-named retardation or acceleration.

These progressive proportions of lead can, however, only be correctlymaintained, in other words, the pure oval dotted course describing thistravel of the slide-valve can only be obtained, by the alterations ofthe proportions of the lead-lever being made to exactly correspond tothe length of stroke of the piston. If, in fact, the course of the lowerlever were shorter than the stroke of the piston, or even equal to zero,the acceleration, and consequently also the proportion of lead, wouldalso be less, while the same would also be diminished to the same extentif the duration of the course were longer, as,

0 for instance, would be the case if the lower end of the lead-levermoved from one point to another on a curved instead of a straight line,so the necessary increase of the levers B D in both cases would nolonger take place in correct proportion to the position of the 4o curveof pure regular course, that is to say,

the solution of the problem is excluded. This extremely simple mode ofconstruction also allows of the further arrangements usual inslide-valves for varying the degree of filling,

5 &c. being used. Thus, for instance, the point B, instead of beingdirectly influenced from the eccentricrod, may be connected with a rodattached to the slide-block of an ordinary connecting-link arrangement,Figs. 4 and 5,

and it suitices, in order to alter the degree of filling, to operate theso-called reversinglever by hand or by means of a regulator. In thesefigures, '1 is the traction-rod E, the slide Stephenson link; Q, theblock, and it the system of levers for the displacement of the link inone way or the other, the lever B being marked with the same letter asin Figs. 2 and 3. According to the displacement which the operatortransfers to the link E by the levers t t the block Q will go forwardand backward, and will consequently displace the point of COlJVGlSlOIl Bof the advance lever, and with it the slide, as in ordinaryslide-valves, so that the admissions of steam are also larger or smallerin proportion to these changing positions.

In non-reversing machines the connectinglink only requires to be halfthe length, and the suitable oval diagrams shown in Fig. 6 are obtainedfor the various positions of the distribution of expansion-lever, thelargest of these ovals corresponding to the maximum filling and thesmaller to the maximum expansion.

I claim- 1. In combination with a valve-gear of a steam-engine, a leverconnected at its lower end with the piston-rod, pivoted at anintermediate point to the eccentric-rod and having its upper free endsuitably connected to the valve-rod, substantially in the manner hereinexplained.

2. In combination with the valve'gear of a steam-engine, a leverestablishing controlling communication between the eccentric-rod andvalve-rod, and having connection with the latter which permits therelative movement between them in a direction transverse to thevalve-rod, and means for sliding the lever transversely of the valve-rodin opposite directions simultaneously with the stroke of the latter andthereby varying the amplitude of the movement imparted to the same atopposite ends of its throw, substantially as herein described.

TROPHIME DELVILLE.

Witnesses:

AUG. J OERISSEN, Louis DELOSTER.

